Low temperature curable organopolysiloxane coatings

ABSTRACT

A method of making a coated substrate which includes the steps of applying a layer of a coating composition, said coating composition comprising an alkenyl functional organopolysiloxane and a hydride functional organopolysiloxane, to the substrate, said substrate comprising a catalytically effective amount of a precious metal catalyst, and allowing the layer to cure, allows the use of a non-catalyzed coating bath having a very long useful life, while providing a highly reactive coating layer that may be rapidly cured at low temperature.

[0001] This application is a Divisional Application of U.S. Ser. No.09/454,932 filed Dec. 3, 1999 which claims rights of priority from U.S.Provisional Patent Application Serial No. 60/156,082, filed Sep. 24,1999. Other Divisional Applications of U.S. Ser. No. 09/454,932 areco-pending.

FIELD OF THE INVENTION

[0002] The present invention relates to a low temperature curablecoatings, more particularly to addition curable organopolysiloxanecoatings that cure rapidly at low temperature.

BRIEF DESCRIPTION OF THE RELATED ART

[0003] Addition curable release coating compositions and their use asrelease coatings are known, see, for example, coassigned U.S. Pat. No.4,448,815. A layer of such coating is typically applied to a substrate,such as paper, from a reactive coating bath which contains analkenyl-functional organopolysiloxane, a hydride-functionalorganopolysiloxane, a precious metal catalyst and a cure inhibitor. Onceapplied, the layer of coating is cured by exposing the coated substrateto elevated temperature.

[0004] The cure inhibitor retards cure of the coating and enables abalance between a long useful coating bath life at low temperature andrapid cure speed at elevated temperature to be maintained. There is aconstant desire in the art to provide increased cure speed withoutcompromising bath life.

[0005] The need to subject the coated substrate to elevated temperatureto cure the coating layer introduces some drawbacks to the use ofaddition cure organopolysiloxane release coatings coating process, inthe form of energy costs, a need to rehydrate coated paper substratesafter curing and a limited ability to use such coatings to coattemperature sensitive substrates, such as, for example, some polymerfilms. Due to these drawbacks, there is a desire in the art to providecoatings that are curable at lower temperature without compromising bathlife.

SUMMARY OF THE INVENTION

[0006] In a first aspect, the present invention is directed to a methodof making a coated substrate.

[0007] In a first embodiment, a method of making a coated substratecomprises: applying a layer of a coating composition, said coatingcomposition comprising an alkenyl functional organopolysiloxane and ahydride functional organopolysiloxane, to a substrate, said substratecomprising a catalytically effective amount of a precious metalcatalyst, and allowing the layer to cure.

[0008] In a second embodiment, a method of making a coated substratecomprises: applying a layer of a first component of a coatingcomposition, said first component comprising an alkenyl functionalorganopolysiloxane and a catalytically effective amount of a preciousmetal catalyst to a substrate, applying a layer a second component of acoating composition, said second component comprising a hydridefunctional organopolysiloxane, to the substrate, and allowing the layersof coating composition to cure.

[0009] In a third embodiment, a method of making a coated substratecomprises: applying a layer of a coating composition, said coatingcomposition comprising organopolysiloxane having both alkenyl andhydride radicals present on the same molecule, to the substrate, saidsubstrate comprising a catalytically effective amount of a preciousmetal catalyst, and allowing the layer to cure.

[0010] The method of the present invention allows the use of anon-catalyzed coating bath having a very long useful life, whileproviding a highly reactive coating layer that may be rapidly cured atlow temperature and thereby avoids some of the drawbacks, for example,high energy costs, the need to rehydrate paper substrates and thelimited applicability to temperature sensitive substrates, thatcharacterize typical addition cure coatings.

[0011] Another aspect of the present invention is directed to acatalyzed article comprising a substrate selected from paper sheets,polymer films, polymer coated paper sheets and metal foils, and aprecious metal catalyst disposed on at least one surface of thesubstrate.

[0012] Another aspect of the present invention is directed to a methodof forming a catalyzed article, comprising: forming a dilute catalyst bydissolving a precious metal catalyst in a volatile organic ororganosiloxane solvent; or by dispersing a precious metal catalyst in abinder composition; or by dispersing a precious metal catalyst in a filmforming polymer composition, and applying the dilute catalyst to thesubstrate, wherein the composition of the dilute catalyst andapplication rate of dilute catalyst on the substrate are selected toprovide a selected amount of precious metal per unit area of substratesurface.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Alkenyl functional organopolysiloxanes suitable for use in themethod of the present invention are those including structural units ofthe formula (I):

R¹ _(a)SiO_(4-a/2)  (I)

[0014] wherein:

[0015] each R¹ is independently hydroxyl or a monovalent hydrocarbonradical, and

[0016] a is an integer wherein 0≦a≦3,

[0017] provided that at least two R¹ groups per molecule of such alkenylfunctional organopolysiloxane are each independently alkenyl radicals.

[0018] As used herein “monovalent hydrocarbon radical” means amonovalent acyclic hydrocarbon radical, a monovalent alicyclichydrocarbon radical or a monovalent aromatic hydrocarbon radical.

[0019] As used herein, the terminology “acyclic hydrocarbon radical”means a monovalent straight chain or branched hydrocarbon radical,preferably containing from 2 to 20 carbon atoms per radical, which maybe saturated or unsaturated and which may be optionally substituted orinterrupted with one or more functional groups, such as, for example,carboxyl, cyano, hydroxy, halo and oxy. Suitable monovalent acyclichydrocarbon radicals include, for example, alkyl, alkenyl, alkynyl,hydroxyalkyl, cyanoalkyl, carboxyalkyl, carboxamide, alkylamido andhaloalkyl, such as, for example, methyl, ethyl, sec-butyl, tert-butyl,octyl, decyl, dodecyl, cetyl, stearyl, ethenyl, propenyl, butynyl,hydroxypropyl, cyanoethyl, carboxymethyl, chloromethyl and3,3,3-fluoropropyl.

[0020] As used herein the term “alkyl” means a saturated straight orbranched monovalent hydrocarbon radical. In a preferred embodiment,monovalent alkyl groups are selected from linear or branched alkylgroups containing from 1 to 12 carbons per group, such as, for example,methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl,tert-butyl, pentyl, hexyl, heptyl, decyl, dodecyl.

[0021] As used herein the term “alkenyl” means a straight or branchedmonovalent terminally unsaturated hydrocarbon radical, preferablycontaining from 2 to 10 carbon atoms per radical, such as, for example,ethenyl, 2-propenyl, 3-butenyl, 5-hexenyl, 7-octenyl and ethenylphenyl.

[0022] As used herein, the terminology “monovalent alicyclic hydrocarbonradical” means a monovalent radical containing one or more saturatedhydrocarbon rings, preferably containing from 4 to 10 carbon atoms perring, per radical which may optionally be substituted on one or more ofthe rings with one or more alkyl radicals, each preferably containingfrom 2 to 6 carbon atoms per group, halo radicals or other functionalgroups and which, in the case of a monovalent alicyclic hydrocarbonradical containing two or more rings, may be fused rings. Suitablemonovalent alicyclic hydrocarbon radicals include, for example,cyclohexyl and cyclooctyl.

[0023] As used herein, the terminology “monovalent aromatic hydrocarbonradical” means a monovalent hydrocarbon radical containing one or morearomatic rings per radical, which may, optionally, be substituted on thearomatic rings with one or more alkyl radicals, each preferablycontaining from 2 to 6 carbon atoms per group, halo radicals or otherfunctional groups and which, in the case of a monovalent aromatichydrocarbon radical containing two or more rings, may be fused rings.Suitable monovalent aromatic hydrocarbon radicals include, for example,phenyl, tolyl, 2,4,6-trimethylphenyl, 1,2-isopropylmethylphenyl,1-pentalenyl, naphthyl, anthryl.

[0024] In a preferred embodiment, the alkenyl functionalorganopolysiloxane comprises one or more organopolysiloxane polymers orcopolymer of the formula (II):

M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e)T¹ _(f)T^(vi) _(g)Q_(h)  (II)

[0025] wherein:

[0026] M¹ is R² ₃SiO_(1/2),

[0027] M^(vi) is R³ ₂R⁴SiO_(1/2),

[0028] D¹ is R⁵ ₂SiO_(2/2),

[0029] D^(vi) is R⁶R⁷SiO_(2/2),

[0030] T¹ is R⁸SiO_(3/2),

[0031] T^(vi) is R⁹SiO_(3/2),

[0032] Q is SiO_(4/2),

[0033] each R², R³, R⁵, R⁶ and R⁸ is independently hydroxyl or amonovalent hydrocarbon radical,

[0034] each R⁴, R⁷ and R⁹ is independently alkenyl,

[0035] b, c, d, e, f, g and h are each integers selected to providepolymer a having a viscosity of from 50 to 50,000 centiStokes (“cSt”)and having a desired amount of alkenyl groups per molecule, provided atleast one of c, e and g is greater than 0, so that the alkenylfunctional organopolysiloxane contains at least two alkenyl radicals permolecule.

[0036] In a preferred embodiment, R², R³, R⁵, R⁶ and R⁸ are each(C₁-C₆)alkyl, most preferably methyl, R⁴, R⁷ and R⁹ are eachindependently a terminally unsaturated (C₂-C₆)alkenyl radical, morepreferably, ethenyl or 5-hexenyl.

[0037] In a preferred embodiment, the coefficients b, c, d, e, f, g andh are selected to provide a having a viscosity of from 100 to 1000 cSt,more preferably from 150 to 500 cSt.

[0038] In a more highly preferred embodiment, the alkenyl functionalorganopolysiloxane comprises one or more compounds selected from: linearalkenyl-stopped dialkylsiloxane polymers of the formula M^(vi) ₂D¹ _(d),branched alkenyl-stopped dialkylsiloxane polymers of the formula M¹_(b)M^(vi) _(c)D¹ _(d)T¹ _(f), siloxane polymers of the formula M¹_(b)M^(vi) _(c)Q¹ _(h), alkenyl-stopped alkylalkenyl dialkylpolysiloxanecopolymers of the formula M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e), whereinM¹, M^(vi), D¹, D^(vi), T_(f), Q, b, c, d, e and h are each defined asabove, and wherein R², R³, R⁵, R⁶ and R⁸ are each alkyl, preferablymethyl, and wherein R⁴ and R⁷ are each preferably ethenyl.

[0039] Hydride functional organopolysiloxanes suitable for use in themethod of the present invention are those including structural units ofthe structural formula (III):

R¹⁰ _(i)SiO_(4-i/2)  (III)

[0040] wherein

[0041] each R¹⁰ is independently H or a monovalent hydrocarbon radical,and

[0042] a is an integer wherein 0≦i≦3,

[0043] provided that at least two R¹⁰ groups per molecule of suchhydride functional organopolysiloxane are each H.

[0044] In a preferred embodiment, the hydride functionalorganopolysiloxane is an organopolysiloxane of the structural formula(IV):

M² _(j)M^(H) _(k)D² _(l)D^(H) _(m)T² _(n)T^(H) _(o)Q_(p)  (IV)

[0045] wherein:

[0046] M² is R¹¹ ₃SiO_(1/2),

[0047] M^(H) is R¹² ₂R¹³SiO_(1/2),

[0048] D² is R¹⁴ ₂SiO_(2/2),

[0049] D^(H) is R¹⁵R¹⁶SiO_(2/2),

[0050] T² is R¹⁷SiO_(3/2),

[0051] T^(H) is R¹⁸SiO_(3/2),

[0052] Q is SiO_(4/2),

[0053] each R¹¹, R¹², R¹⁴, R¹⁵ and R¹⁷ is independently a monovalenthydrocarbon radical,

[0054] R¹³, R¹⁶ and R¹⁸ are each H,

[0055] j, k, l, m, n, o and p are each integers selected to provide apolymer having a viscosity of from 1 to 1000 cSt and a desired amount ofsilicon-bonded H radicals per molecule, provided at least one of k, mand o is greater than 0, so that the hydride functionalorganopolysiloxane contains at least two silicon-bonded H radicals permolecule.

[0056] In a preferred embodiment, R¹¹, R¹², R¹⁴ and R¹⁵ are each(C₁-C₆)alkyl, most preferably methyl.

[0057] In a preferred embodiment, the coefficients b, c, d, e, f, g andh are selected to provide a having a viscosity of from 10 to 150 cSt,more preferably from 20 to 80 cSt.

[0058] In a more highly preferred embodiment, the hydride functionalorganopolysiloxane comprises one or more compounds selected fromtrialkylsiloxy-stopped alkyl hydrogen polysiloxanes of the formula M²_(j)D^(H) _(m), trialkylsiloxy-stopped alkylhydrogen dialkylpolysiloxanecopolymers of the formula M² _(j)D² _(l)D^(H) _(m), wherein M², D²,D^(H), j, l and m are each defined as above, and wherein R¹¹, R¹⁴ andR¹⁵ are each alkyl, preferably methyl.

[0059] In an alternative embodiment, the coating composition comprisesan organopolysiloxane having both alkenyl and hydride radicals presenton the same molecule, such as for example the organopolysiloxanesdisclosed in coassigned U.S. Pat. Nos. 5,698,654 and 5,753,751, thedisclosure of which is hereby incorporated herein by reference.

[0060] In a preferred embodiment, the alkenyl and hydride functionalorganopolysiloxane comprises one or more organopolysiloxanes of theformula (V):

M¹ _(q)M^(vi) _(r)M^(H) _(s)D¹ _(s)D^(vi) _(u)D^(H) _(v)T¹ _(w)T^(vi)_(x)T^(H) _(y)Q_(z)  (V)

[0061] wherein; M¹, M^(vi), M^(H)D¹, D^(vi), D^(H), T¹, T^(vi), T^(H), Qare each defined as above and q, r, s, t, u, v, w, x, y and z are eachintegers selected to provide polymer a having a viscosity of from 50 to50,000 cSt and having a desired amount of alkenyl groups andsilicon-bonded H radicals per molecule, provided that each moleculecontains at least two alkenyl groups and at least two silicon-bonded Hradicals.

[0062] In a preferred embodiment coating composition exhibits a molarratio of silicon bonded hydrogen on the hydride functionalorganopolysiloxane to alkenyl groups on the alkenyl functionalorganopolysiloxane (“Si—H:alkenyl ratio”) of from 1:5 to 5:1, morepreferably from 1:1 to 4:1 and even more preferably from 1.2:1 to 2.5:1.

[0063] The coating composition used in the method of the presentinvention may optionally include other components known in the art, suchas, for example, nonreactive diluents, such as for example, solventssuch as water, hydrocarbon fluids and non-functionalized silicone oils,reactive diluents, such as, for example, vinyl ether compounds, cureinhibitors, cure rate accelerators, fillers, controlled releaseadditives and colorants.

[0064] Substrates suitable for use in the method of the presentinvention include paper, such as for example, supercalendered kraftpaper, glassine paper, machine finished paper and machine glazed paper,and polymer films, such as, for example, polyolefins, polyesters andpolystyrenics, metal foils, such as for example, aluminum foil andcomposite substrates, such as for example, polyolefin coated kraftpaper.

[0065] Precious metal catalysts suitable for use in the method of thepresent invention are those capable of catalyzing the cure of anaddition curable siloxane coating composition. In a preferredembodiment, the precious metal catalyst comprises one or more ofplatinum and rhodium. Suitable precious metal catalysts include, forexample, chloroplatinic acid, precious metal salts, such as for example,sodium or potassium salts of chloroplatinic acid, platinum halides,organometallic complexes, such as, for example, Karstedt's catalyst,platinum cyclohexadiene complex, platinum acetyl acetonate complex, aswell as olefinic ligands of platinum or rhodium, and supported preciousmetal catalysts, such as platinum deposited on silica or aluminaparticles, which provide the precious metal in a form that is suitablefor catalyzing the cure of the organopolysiloxane mixture of the coatingcomposition used in the method of the present invention. In a preferredembodiment, the precious metal catalyst comprises a platinum complex ofdivinyl tetramethyl disiloxane.

[0066] In a preferred embodiment, a dilute form of the precious metalcatalyst is made by dissolving the catalyst in a solvent, such as forexample, hexane, heptane, octane or a mixture thereof or anorganopolysiloxane, or by dispersing the catalyst in a bindercomposition, for example, a binder composition for finishing papercomprising a polymer latex and an inorganic filler, or by dispersing thecatalyst in a film forming polymer composition, such as, for example,polyvinyl alcohol or a polyacrylate composition, and the dilute form ofcatalyst is applied to the substrate, by for example, spray coating,roll coating, rod coating or extrusion, to form a precious metalcatalyst-containing substrate.

[0067] Alternatively, the catalyst is dissolved in an alkenyl functionalorganopolysiloxane and a layer of the an alkenyl functionalorganopolysiloxane/catalyst solution is applied to the substrate.

[0068] As used herein, “catalytically effective amount” means an amounteffective to catalyze the cure of a layer of coating disposed on thesubstrate. In a preferred embodiment, the precious metalcatalyst-containing substrate contains greater than about 0.000001 g,more preferably from 0.00005 to 0.01 g, and still more preferably, from0.0005 to 0.001 g, of precious metal per square meter of substratesurface.

[0069] A layer of the coating composition is applied to the substrate byfor example, spray coating, roll coating, rod coating or extrusion andallowed to cure. The layer of coating composition may be allowed to cureat uncontrolled ambient temperature or may be allowed to cure at anelevated temperature, such as for example, a temperature of up to about100° C., more preferably up to about 70° C., and still more preferably,up to about 40° C.

[0070] The coated substrate made by the method of the present inventionis useful a release liner for pressure sensitive adhesive-backedarticles such as, for example, adhesive labels and adhesives tapes.

[0071] An adhesive laminate comprises a coated substrate made by themethod of the present invention laminated with a pressure sensitiveadhesive coated substrate, such that the cured coating layer of thecoated substrate made by the method of the present invention is incontact with the pressure sensitive adhesive layer on the pressuresensitive adhesive coated substrate. Suitable pressure sensitiveadhesive compositions, such as, for example, emulsion acrylic adhesives,solvent acrylic adhesives, hot melt adhesives, emulsion rubber adhesive,solvent rubber adhesives, and methods for making pressure sensitiveadhesive coated substrates are well known in the art. The pressuresensitive adhesive coated substrate may be easily removed from thecoated substrate made by the method of the present invention and appliedto another substrate, as desired.

EXAMPLE 1

[0072] A paper substrate (super-calendered kraft paper) was coated witha xylene solution of Karstedt's catalyst by applying approximated 1milliliter of a 5% platinum by weight solution to a 6 inch by 3 inchpaper sheet and then allowing the xylene to evaporate. A layer of acoating composition containing 5 grams of a vinyl stoppeddimethylsiloxane polymer (structural formula M^(vi) ₂D¹ _(d), whereinM^(vi), D¹ and d are each as described above, and R³ and R⁵ are eachmethyl, R⁴ is ethenyl, and exhibiting a viscosity of about 250 cSt) and0.5 grams of a trimethylsiloxy-stopped methylhydrogen dimethylsiloxanepolymer (formula M² ₂D² _(l)D^(H) _(m), wherein M², D², D^(H), l and mare each as described above, R¹¹, R¹⁴ and R¹⁵ are each methyl and R¹⁶ isH, containing approximately 1 wt % hydride radicals and exhibiting aviscosity of about 35 cSt) was applied to the platinum-containing papersubstrate in a bead and drawn down across the paper with a straightmetal edge. Cure was qualitatively assessed by rubbing the layer with afingertip immediately after application of the coating layer to thesubstrate. The coating did not smear, indicating that the coating hadcured very rapidly at room temperature.

EXAMPLE 2

[0073] A hexenyl-stopped polydimethyl siloxane polymer (structuralformula M^(vi) ₂D¹ _(d), wherein M^(vi), D¹ and d are each as describedabove, R³ and R⁵ are each methyl, and R⁴ is hexenyl, and exhibiting aviscosity of about 250 cSt) was mixed with Karstedt's catalyst to make amixture containing 270 parts per million platinum. Theplatinum-catalyzed polysiloxane mixture was applied to a paper substrate(super-calendered kraft paper) by the same technique as described abovein Example 1. The coated paper was then coated with a layer of thetrimethylsiloxy-stopped methylhydrogen dimethylsiloxane polymerdescribed above in Example 1. The coating was found to have cured within15 seconds of the application of the trimethylsiloxy-stoppedmethylhydrogen dimethylsiloxane polymer.

EXAMPLE 3

[0074] A solution of a platinum divinyl tetramethyl siloxane complex inhexane (0.5% Pt) was coated on Kammerer AV100 glassine paper using a #3Meyer rod and the solvent was then flashed off for 10 seconds at 160° F.in a forced air oven to form a Pt coated paper substrate. A mixture of50 parts by weight (“pbw”) of a vinyl-stopped dimethylsiloxane polymer(formula M^(vi) ₂D¹ _(d), wherein M^(vi), D¹ and d are each as describedabove, and R³ and R⁵ are each methyl, R⁴ is ethenyl, and exhibiting aviscosity of about 225 cSt) and 2.5 pbw of the trimethylsilyl-stoppedmethylhydrogen dimethyl polysiloxane copolymer used in Example 1 werecoated on top of the Pt-coated paper using a doctor blade. The liquidcoating was found to cure almost immediately on contact with thePt-coated paper substrate.

[0075] The extent of cure was qualitatively assessed by a tape migrationtest and rubbing the surface of the cured siloxane coating layer with afingertip. The tape migration test was conducted by firmly pressing theadhesive side of a piece of 3M Scotch® 610 tape to the surface of thecured siloxane coating, peeling the tape off and then making a loop ofthe tape such that the adhesive side of the tape was brought intocontact with itself. Migration of uncured siloxane coating to theadhesive side of the tape would interfere with the ability of the tapeto stick to itself. The surface of the cured coating layer was thenrubbed vigorously with a fingertip and then the surface was visuallyexamined. Smearing of the coating layer was taken as being indicative ofan incompletely cured coating layer. The relative difficulty of markingthe coating, that is, making visually detectable deformations of thecoating surface, by fingertip rubbing was taken as being indicative ofthe hardness of the cured coating layer, with increasing difficulty inmarking being indicative of greater hardness.

[0076] The tape migration test for the coating of Example 3 showed thatthe tape stuck to itself well, indicating that it had not beencontaminated with a significant amount of silicone. The coating ofExample 3 did not smear, but could be marked fairly easily when thesurface of the coating was rubbed with a fingertip.

EXAMPLE 4

[0077] The procedure of Example 3 was repeated, except that the siliconecoated paper, was place in a forced air oven at 160° F. for 5 secondsimmediately after coating the paper with the silicone mixture.

[0078] The tape migration test for the coating of Example 4 showed thatthe tape stuck to itself well, indicating that it had not beencontaminated with a significant amount of silicone. The coating ofExample 4 did not smear, but could be marked somewhat when the surfaceof the coating was rubbed with a fingertip.

EXAMPLE 5

[0079] The procedure of Example 3 was repeated, except that Thilmanypolyethylene kraft (PEK) substrate was substituted for the KammererAV100 glassine paper.

[0080] The tape migration test for the coating of Example 5 showed thatthe tape stuck to itself well, indicating that it had not beencontaminated with a significant amount of silicone. The coating ofExample 5 did not smear and exhibited no marking when the surface of thecoating was rubbed with a fingertip.

EXAMPLE 6

[0081] The procedure of Example 5 was repeated, except that the siliconeformulation used was a mixture of 50 pbw of a branched alkenylfunctional polymer (approximate structure M^(vi) _(3.75)M¹ _(0.5)T¹_(4.5)D¹ ₁₀₀, wherein M¹, M^(vi), T¹ and D¹ are each defined as above,with R², R³, R⁵ and R⁸ each being methyl and R⁴ being ethenyl, andexhibiting a viscosity of 208 cSt) and 3.0 pbw of the methyl hydrogendimethyl polysiloxane copolymer used in Example 3.

[0082] The tape migration test for the coating of Example 6 showed thatthe some migration to the tape immediately after coating, as evidencedby the fact that the tape did not stick well to itself after being incontact with the siloxane coating layer. The coating of Example 6smeared when rubbed with a fingertip. A recheck after about a minuteshowed no migration to the tape and no smearing of the coating.

EXAMPLE 7

[0083] The procedure of Example 3 was repeated, except that a 2 milpolyester film was substituted for was substituted for the KammererAV100 glassine paper used in Example 3.

[0084] The tape migration test for the coating of Example 7 showed thatthe tape stuck to itself well, indicating that it had not beencontaminated with a significant amount of silicone. The coating ofExample 7 did not smear and exhibited some marking when the surface ofthe coating was rubbed with a fingertip.

EXAMPLE 8

[0085] The silicone coating composition of Example 6 was coated on aPt-treated 2 mil polyester film and then heated at 160° F. for 10seconds.

[0086] The tape migration test for the coating of Example 8 showed thatthe tape stuck to itself well, indicating that it had not beencontaminated with a significant amount of silicone. The coating ofExample 8 did not smear and exhibited some marking when the surface ofthe coating was rubbed with a fingertip.

[0087] The method of the present invention allows the use of anon-catalyzed coating bath having a very long useful life, whileproviding a highly reactive coating layer that may be rapidly cured atlow temperature and thereby avoids some of the drawbacks, for example,high energy costs, the need to rehydrate paper substrates and thelimited applicability to temperature sensitive substrates, thatcharacterize typical addition cure coatings.

1. A method of making a coated substrate, comprising applying a coatingcomposition, said coating composition comprising an alkenyl functionalcompound and a hydride functional compound, to a substrate, saidsubstrate comprising a catalytically effective amount of a preciousmetal catalyst, and allowing the coating composition to cure.
 2. Themethod of claim 1, wherein the alkenyl functional compound comprises anorganopolysiloxane comprising structural units of the formula: R¹_(a)SiO^(4-a/2) wherein each R¹ is independently hydroxyl or amonovalent hydrocarbon radical, and a is an integer wherein 0≦a≦3 andprovided that at least two R¹ groups per molecule of such alkenylfunctional organopolysiloxane are each independently alkenyl radicals.3. The method of claim 1, wherein the alkenyl functional compoundcomprises one or more organopolysiloxane polymers or copolymers of theformula: M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e)T¹ _(f)T^(vi) _(g)Q_(h)wherein: M¹ is R² ₃SiO_(1/2), M^(vi) is R³ ₂R⁴SiO_(1/2), D¹ is R⁵₂SiO_(2/2), D^(vi) is R⁶R⁷SiO_(2/2), T¹ is R⁸SiO_(3/2), T^(vi) isR⁹SiO_(3/2), Q is SiO_(4/2), each R², R³, R⁵, R⁶ and R⁸ is independentlyhydroxyl or a monovalent hydrocarbon radical, each R⁴, R⁷ and R⁹ isindependently alkenyl, b, c, d, e, f, g and h are each integers selectedto provide polymer a having a viscosity of from 50 to 50,000centiStokes, provided at least one of c, e and g is greater than 0 andthe alkenyl functional organopolysiloxane contains at least two alkenylradicals per molecule.
 4. The method of claim 1, wherein the hydridefunctional compound comprises an organopolysiloxane comprisingstructural units of the structural formula: R¹⁰ _(i)SiO_(4-i/2) whereineach R¹⁰ is independently H or a monovalent hydrocarbon radical, and ais an integer wherein 0≦i≦3, provided that at least two R¹⁰ groups permolecule of such hydride functional organopolysiloxane are each H. 5.The method of claim 1, wherein the hydride functional compound comprisesone or more organopolysiloxanes of the structural formula: M² _(j)M^(H)_(k)D² _(l)D^(H) _(m)T² _(n)T^(H) _(o)Q_(p) wherein: M² is R¹¹₃SiO_(1/2), M^(H) is R¹² ₂R¹³SiO_(1/2), D² is R¹⁴ ₂SiO_(2/2), D^(H) isR¹⁵R¹⁶SiO_(2/2), T² is R¹⁷SiO_(3/2), T^(H) is R¹⁸SiO_(3/2), Q isSiO_(4/2), each R¹¹, R¹², R¹⁴, R¹⁵ and R¹⁷ is independently a monovalenthydrocarbon radical, R¹³, R¹⁶ and R¹⁸ are each H, j, k, l, m, n, o and pare each integers selected to provide a polymer having a viscosity offrom 1 to 1000 centiStokes, provided at least one of k, m and o isgreater than 0 and the hydride functional organopolysiloxane contains atleast two silicon-bonded H radicals per molecule.
 6. The method of claim1, wherein the substrate comprises paper, a polymer film, a metal foilor a combination thereof.
 7. The method of claim 1, wherein the preciousmetal catalyst comprises one or more of platinum and rhodium.
 8. Themethod of claim 1, wherein the catalytically effective amount ofprecious metal catalyst is an amount greater than about 0.000001 gram ofprecious metal catalyst per square meter of substrate surface.
 9. Themethod of claim 1, wherein the catalytically effective amount ofprecious metal catalyst is an amount of from 0.00005 gram to 0.01 gramof precious metal catalyst per square meter of substrate surface. 10.The method of claim 1, wherein the catalytically effective amount ofprecious metal catalyst is an amount of from 0.0005 gram to 0.001 gramof precious metal per square meter of substrate surface.
 11. The methodof claim 1, wherein a layer of the coating composition is applied to thesubstrate by spray coating, roll coating, rod coating or extrusion. 12.The method of claim 1, wherein the layer of coating composition isallowed to cure at uncontrolled ambient temperature or at an elevatedtemperature.
 13. The method of claim 12, wherein the layer of coatingcomposition is allowed to cure at uncontrolled ambient temperature. 14.The method of claim 12, further comprising allowing the layer of coatingcomposition to cure at an elevated temperature of up to about 100° C.15. A coated substrate made by the method of claim
 1. 16. A laminate,comprising a coated substrate made by the method of claim 1, and apressure sensitive adhesive coated substrate, comprising a secondsubstrate and a layer of a pressure sensitive adhesive on the secondsubstrate, disposed such that the pressure sensitive adhesive layer isin contact with the cured coating layer of the coated substrate.
 17. Amethod of making a coated substrate, comprising applying a layer of afirst component of a coating composition, said first componentcomprising an alkenyl functional organopolysiloxane and a catalyticallyeffective amount of a precious metal catalyst to a substrate, applying alayer a second component of a coating composition, said second componentcomprising a hydride functional organopolysiloxane to the substrate, andallowing the layers of coating composition to cure.
 18. A coatedsubstrate made by the process of claim
 17. 19. A method of making acoated substrate, comprising applying a layer of a coating composition,said coating composition comprising an organopolysiloxane having bothalkenyl and hydride radicals present on the same molecule, to thesubstrate, said substrate comprising a catalytically effective amount ofa precious metal catalyst, and allowing the layer to cure.
 20. Themethod of claim 19, wherein the organopolysiloxane comprises one or moreorganopolysiloxanes of the formula: M¹ _(q)M^(vi) _(r)M^(H) _(s)D₁_(s)D^(vi) _(u)D^(H) _(v)T¹ _(w)T^(vi) _(x)T^(H) _(y)Q_(z) wherein; M¹is R² ₃SiO_(1/2), M^(vi) is R³ ₂R⁴SiO_(1/2), D¹ is R⁵ ₂SiO_(2/2), D^(vi)is R⁶R⁷SiO_(2/2), T¹ is R⁸SiO_(3/2), T^(vi) is R⁹SiO_(3/2), Q isSiO_(4/2), M^(H) is R¹² ₂R¹³SiO_(1/2), D^(H) is R¹⁵R¹⁶SiO_(2/2), T^(H)is R¹⁸SiO_(3/2), and q, r, s, t, u, v, w, x, y and z are each integersselected to provide polymer a having a viscosity of from 50 to 50,000centistokes, provided that each molecule contains at least two alkenylgroups and at least two silicon-bonded H radicals.
 21. A coatedsubstrate made by the process of claim
 19. 22. A system for making acoated substrate, comprising a coating composition, said coatingcomposition comprising an alkenyl functional compound and a hydridefunctional compound, and a substrate having a precious metal catalystdisposed on at least one surface of the substrate in an amount effectiveto catalyze cure of the coating composition when the coating compositionis applied to the substrate.
 23. The system of claim 22, wherein thesubstrate is selected from papers, polymers films, metal foils andcombinations thereof.
 24. The system of claim 22, wherein the alkenylfunctional compound comprises an organopolysiloxane comprisingstructural units of the formula: R¹ _(a)SiO_(4-a/2) wherein each R¹ isindependently hydroxyl or a monovalent hydrocarbon radical, and a is aninteger wherein 0≦a≦3 and provided that at least two R¹ groups permolecule of such alkenyl functional organopolysiloxane are eachindependently alkenyl radicals.
 25. The system of claim 22, wherein thealkenyl functional compound comprises one or more organopolysiloxanepolymers or copolymers of the formula: M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi)_(e)T¹ _(f)T^(vi) _(g)Q_(h) wherein: M¹ is R² ₃SiO_(1/2), M^(vi) is R³₂R⁴SiO_(1/2), D¹ is R⁵ ₂SiO_(2/2), D^(vi) is R⁶R⁷SiO_(2/2), T¹ isR⁸SiO_(3/2), T^(vi) is R⁹SiO_(3/2), Q is SiO_(4/2), each R², R³, R⁵, R⁶and R⁸ is independently hydroxyl or a monovalent hydrocarbon radical,each R⁴, R⁷ and R⁹ is independently alkenyl, b, c, d, e, f, g and h areeach integers selected to provide polymer a having a viscosity of from50 to 50,000 centiStokes, provided at least one of c, e and g is greaterthan 0 and the alkenyl functional organopolysiloxane contains at leasttwo alkenyl radicals per molecule.
 26. The system of claim 22, whereinthe hydride functional compound comprises an organopolysiloxanecomprising structural units of the structural formula: R¹⁰_(i)SiO_(4-i/2) wherein each R¹⁰ is independently H or a monovalenthydrocarbon radical, and a is an integer wherein 0≦i≦3, provided that atleast two R¹⁰ groups per molecule of such hydride functionalorganopolysiloxane are each H.
 27. The system of claim 22, wherein thehydride functional compound comprises one or more organopolysiloxanes ofthe structural formula: M² _(j)M^(H) _(k)D² _(l)D^(H) _(m)T² _(n)T^(H)_(o)Q_(p) wherein: M² is R¹¹ ₃SiO_(1/2), M^(H) is R¹² ₂R¹³SiO_(1/2), D²is R¹⁴ ₂SiO_(2/2), D^(H) is R¹⁵R¹⁶SiO_(2/2), T² is R¹⁷SiO_(3/2), T^(H)is R¹⁸SiO_(3/2), Q is SiO_(4/2), each R¹¹, R¹², R¹⁴, R¹⁵ and R¹⁷ isindependently a monovalent hydrocarbon radical, R¹³, R¹⁶ and R¹⁸ areeach H, j, k, l, m, n, o and p are each integers selected to provide apolymer having a viscosity of from 1 to 1000 centiStokes, provided atleast one of k, m and o is greater than 0 and the hydride functionalorganopolysiloxane contains at least two silicon-bonded H radicals permolecule.
 28. The system of claim 22, wherein the alkenyl functionalcompound and the hydride functional compound comprise one or moreorganopolysiloxanes of the formula: M¹ _(q)M^(vi) _(r)M^(H) _(s)D¹_(s)D^(vi) _(u)D^(H) _(v)T¹ _(w)T^(vi) _(x)T^(H) _(y)Q_(z) wherein; M¹is R² ₃SiO_(1/2), M^(vi) is R³ ₂R⁴SiO_(1/2), D¹ is R⁵ ₂SiO_(2/2), D^(vi)is R⁶R⁷SiO_(2/2), T¹ is R⁸SiO_(3/2), T^(vi) is R⁹SiO_(3/2), Q isSiO_(4/2), M^(H) is R¹² ₂R¹³SiO_(1/2), D^(H) is R¹⁵R¹⁶SiO_(2/2), T^(H)is R¹⁸SiO_(3/2), and q, r, S, t, u, v, w, x, y and z are each integersselected to provide polymer a having a viscosity of from 50 to 50,000centiStokes provided that each molecule contains at least two alkenylgroups and at least two silicon-bonded H radicals.
 29. The system ofclaim 22, wherein the precious metal catalyst comprises one or more ofplatinum and rhodium.
 30. The system of claim 22, wherein the preciousmetal catalyst is disposed on at least one surface of the substrate inan amount greater than about 0.000001 gram of precious metal catalystper square meter of substrate surface.
 31. The system of claim 22,wherein the precious metal catalyst is disposed on at least one surfaceof the substrate in an amount of from 0.00005 gram to 0.01 gram ofprecious metal catalyst per square meter of substrate surface.
 32. Thesystem of claim 22, wherein the precious metal catalyst is disposed onat least one surface of the substrate in an amount of from 0.0005 gramto 0.001 gram of precious metal per square meter of substrate surface.33. A catalyzed article, comprising a substrate selected from papers,polymer films, polymer coated papers, metal foils and combinationsthereof, and a precious metal catalyst disposed on at least one surfaceof the substrate.
 34. The article of claim 33, wherein the preciousmetal catalyst comprises one or more of platinum and rhodium.
 35. Thearticle of claim 33, wherein the precious metal catalyst comprisesplatinum.
 36. The article of claim 33, wherein the precious metalcatalyst comprises one or more of chloroplatinic acid, sodium orpotassium salts of chloroplatinic acid, platinum halides, Karstedt'scatalyst, platinum cyclohexadiene complex, platinum complex of divinyltetramethyl disiloxane, platinum acetyl acetonate complex, olefinicligands of platinum or rhodium, platinum deposited on silica or aluminaparticles.
 37. The article of claim 33, wherein the precious metalcatalyst disposed on at least one surface of the substrate in an amountgreater than about 0.000001 gram of precious metal catalyst per squaremeter of substrate surface.
 38. The article of claim 33, wherein theprecious metal catalyst disposed on at least one surface of thesubstrate in an amount of from 0.00005 gram to 0.01 gram of preciousmetal catalyst per square meter of substrate surface.
 39. The article ofclaim 33, wherein the precious metal catalyst disposed on at least onesurface of the substrate in an amount of from 0.0005 gram to 0.001 gramof precious metal per square meter of substrate surface.
 40. A methodfor making a catalyzed article, comprising applying a selected amount ofa precious metal catalyst to at least one surface of a substrate. 41.The method of claim 40, further comprising making a dilute form of theprecious metal catalyst, wherein the precious metal catalyst is appliedto the substrate as the dilute form of the catalyst.
 42. The method ofclaim 40, wherein the dilute form of the precious metal catalyst isformed by dissolving the catalyst in a solvent, by dispersing thecatalyst in a binder composition or by dispersing the catalyst in afilm-forming composition.
 43. The method of claim 40, wherein theprecious metal catalyst comprises on or more of platinum or rhodium. 44.The method of claim 40, wherein the dilute catalyst is formed bydissolving a precious metal catalyst in a volatile organic ororganosiloxane solvent comprising one or more of hexane, heptane, octaneand organopolysiloxanes.
 45. The method of claim 40, wherein the dilutecatalyst is formed by dispersing a precious metal catalyst in a bindercomposition comprising a polymer latex and an inorganic filler,
 46. Themethod of claim 40, wherein the dilute catalyst is formed by dispersinga precious metal catalyst in a film-forming polymer composition the filmcomprising a film-forming polyvinyl alcohol composition or afilm-forming polyacrylate composition.
 47. The method of claim 40,wherein the dilute catalyst is applied to the substrate by spraycoating, roll coating, rod coating or extrusion.
 48. The method of claim40, wherein the selected amount of precious metal catalyst is greaterthan about 0.000001 gram of precious metal catalyst per square meter ofsubstrate surface.
 49. The article of claim 40, wherein the selectedamount of precious metal catalyst is from 0.00005 gram to 0.01 gram ofprecious metal catalyst per square meter of substrate surface.
 50. Thearticle of claim 40, wherein the selected amount of precious metalcatalyst is from 0.0005 gram to 0.001 gram of precious metal per squaremeter of substrate surface.
 51. A catalyzed article made by the methodof claim 40.